When the intervertebral disc arranged between two vertebrae is damaged, the nucleus pulposus which the disc encloses in its interior can seep out of the disc through the damaged zone causing a disc herniation. This hernia often results in pain as a result of the hernia contacting nerves in the surrounding area. Damage to surrounding nerves may also occur. For this reason it is necessary to remove the hernia and repair the damaged zone of the disc in order to retain the nucleus within the disc and thus prevent re-herniation.
Devices for retaining the leakage of the nucleus pulposus caused by the rupture of the intervertebral disc are known. For example, U.S. Publication No. US2008/0082168 discloses a device that consists of a band to be applied against the rupture of the vertebral disc which is fixed in position by means of a plurality of strips forming loops that go through respective perforations made in the vertebrae immediately above and below the disc to be repaired. This means that the perforations have to be made prior to the insertion of the device, which complicates the process of implanting the device. In addition to being difficult to implant, the devices require the surgeon to be skilful not only in passing the strips through the perforations, but also in subsequently tying them and all this without the band losing tension.
International Publication WO2010/40107 discloses a system for repairing a herniated intervertebral disc by means of applying a patch-like mesh which covers the herniated disc. The mesh is anchored to the vertebrae immediately above and below the disc to be repaired by means of elements in the form of a hook or fasteners. The mesh is capable of being folded for the introduction thereof in the repair zone and subsequently anchored. The system requires first having the mesh and then correctly maintaining its position while the hooks or fasteners are secured, making the correct fixing thereof difficult.
Devices for repairing a damaged zone in an intervertebral disc by means of sutures are also known, For example, International Publication WO2006/119034 discloses a device formed by a suture thread and a set of anchors for its fastening in the intervertebral disc. The device allows suturing the damaged zone of the intervertebral disc by means of introducing an expandable support inside the disc in which the anchors of the thread are tacked through the disc. These anchors allow securing the suture to the disc and thus being able to close the damaged zone. If the damaged zone of the disc is close to its upper or lower end, the device can further incorporate a point for anchoring the suture in the vertebra adjacent to the damaged zone, as shown in the alternative variant described in International Publication WO2010/045179. A problem associated with such devices that are formed by suture is that they are not very rigid and are therefore difficult to be correctly inserted. Furthermore, the suture can weaken over time, even break, as the zone of the disc to which it is secured gives, for example if the damaged zone of the disc becomes larger.
International Publication WO02058599 discloses another type of osteoimplantable device that consists of an expandable plug acting as a stopper filling the damaged zone of the disc and anchoring means for anchoring the stopper which allows fixing the stopper to the vertebrae adjacent to the plugged disc, preventing the plug from moving. To implant such devices it is necessary for the opening made in the patient's body to be the size of the intervertebral space in order to introduce it. As a result, such devices cannot be implanted in a minimally invasive manner. Such devices also require the surgeon to fix the device to the vertebra after having introduced the plug in the damaged zone of the disc, making it difficult to keep the plug in the correct position during the fixing operation.
A first objective of the resent invention is to disclose an alternative to known osteoimplantable devices for use in repairing an intervertebral disc.
Another objective of the present invention is to disclose an osteoimplantable device for repairing a rupture of an intervertebral disc that is compact and requires minimally invasive surgery.
It is also desirable for the device to not protrude from the vertebra towards the space occupied by the nerve.
Another objective of the present invention is to also disclose an osteoimplantable device for repairing a rupture of an intervertebral disc which allows being adapted to the variations that the intervertebral space may experience, for example due to the reduction of the intervertebral space as a result of degenerative changes, such as spondylitis.